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Noise

You will get a little extra noise with the piston in there along with the x-valve. (found that out the hard way) It will affect capacity and superheat. The x-valve must also have the superheat adjusted. Goodman and Amana use the same x-valve for 2 differant sizes it must be adjusted for the application.

Rheem: I was told by the factory rep to take the pistons out and throw them away. They would cause a rattle and possible a whistle after unit sat off cycle for awhile.

A local Rheem dealer played a HO supplied tape recording which sounded like a thumping or chattering noise, thats what they said was the problem. idk

Originally Posted by meoberry

You will get a little extra noise with the piston in there along with the x-valve. (found that out the hard way) It will affect capacity and superheat. The x-valve must also have the superheat adjusted. Goodman and Amana use the same x-valve for 2 differant sizes it must be adjusted for the application.

Rheem: I was told by the factory rep to take the pistons out and throw them away. They would cause a rattle and possible a whistle after unit sat off cycle for awhile.

I've often wondered about this scenario. Rheem/Ruud uses, or at least used to, an over bored piston in conjunction with a TXV on their flex coils. We were told this was to more evenly distribute the TXV metered refrigerant to the distribution tubes.

Since Goodman coils used on systems that are higher then 13 SEER are designed for higher capacity 13 SEER systems, they therefore have oversized pistons for the higher capacity systems. For example, this 3 ton system is using a coil that has a piston that is designed for use with a 5 ton (13 SEER) system.

Since the piston is so oversized for the 3 ton system, will it really have any adverse affect being in the system after a TXV?

Robo,
You and Beenthere are correct, Rheem/Rudd have and do still use a piston/orifice in some TXV systems.
On the older "multiflex/M" coils, you could use their Add-on TXV kit that came with a "matched" orifice. On the 3 ton coil TXV kit, it was .14 orifice, vs the .65 piston that came with the coil..

You guys where right about the blower speed it was set to high which is 4 ton cooling. How does this effect my system. The manual says for 3 ton cooling set blower speed to medium low.

Overall operation, and humidity removal will be affected. That medium low setting is based on a static pressure, which needs to be checked before proper speed can be determined. Thanks again for the video beenthere!

You will get a little extra noise with the piston in there along with the x-valve. (found that out the hard way) It will affect capacity and superheat. The x-valve must also have the superheat adjusted. Goodman and Amana use the same x-valve for 2 differant sizes it must be adjusted for the application.

Rheem: I was told by the factory rep to take the pistons out and throw them away. They would cause a rattle and possible a whistle after unit sat off cycle for awhile.

You should apply for pro-membership.

This particular situation would have a grossly oversized piston still in place. Why would there be any noise?

TXV's don't care about capacity other then what they are capable of metering. It is the sensing bulb temperature in conjunction with pressure that causes the TXV operation due to preset superheat measuring. Adjustments are only needed if the superheat were not correct, not because there are different capacities.

Rheem/Ruud had back flow preventor rattles a few years back, but never heard of piston rattles. I have heard older Trane units with the whistling issue during pressure equalization after shut down, but not Rheem/Ruud.

If it's a current Goodman coil and a TX_ _ _ kit with a Parker TXV I doubt they left the piston in. On those TXVs there is a little tit that is manufactured on the outlet of the TXV. I've been told that tit is to idiot proof the TXV installation. You can't leave the piston in and still install the TXV. It won’t fit. So I've been told.

I of course have never tried to install a TXV without taking out the piston.

Well, you got me curious enough to dig out an old orifice assembly and a new Parker TXV and you are correct. There is no way that nipple/tit on the txv will allow the txv to be installed if the piston is still in there.

Rattles

Originally Posted by RoBoTeq

You should apply for pro-membership.

This particular situation would have a grossly oversized piston still in place. Why would there be any noise?

TXV's don't care about capacity other then what they are capable of metering. It is the sensing bulb temperature in conjunction with pressure that causes the TXV operation due to preset superheat measuring. Adjustments are only needed if the superheat were not correct, not because there are different capacities.

Rheem/Ruud had back flow preventor rattles a few years back, but never heard of piston rattles. I have heard older Trane units with the whistling issue during pressure equalization after shut down, but not Rheem/Ruud.

Yes. I had one about two years ago. It took a couple of trips to figuire out, because it would only d it when the temp. inside and the temp. outside where just right and the unit had been sitting idle for at least half an hour. It would come on and sound like a mini jackhammer going off, before you could get a cover off it would quit. Removed the piston (per service rep.) Hasn't made the noise since. That was an older Rheem 5 ton 12 seer split heatpump.
Don't recall the model number. That was the only one I ever had do that. But made it a habit of removing pistons behind txv ever since Did not notice any change in superheat or subcooling. Customer was happy. Thats all that really matters.

I did have a mixed system rheem airhandler on a goodman condensor. Had a very loud whistle while running. (was installed by a onetrucker) Found he had installed a txv without removing the original piston which was a .79. Didn't cool very well that way.

Well, you got me curious enough to dig out an old orifice assembly and a new Parker TXV and you are correct. There is no way that nipple/tit on the txv will allow the txv to be installed if the piston is still in there.

Thanks, I was tooooo lazy to get off my butt and walk the 20 feet to my truck and do it myself.